High-efficient preparation of gasoline-ranged C5–C6 alkanes from biomass-derived sugar polyols of sorbitol over Ru-MoO3−x/C catalyst

Abstract

The conversion of biomass-derived sugar polyols to gasoline-ranged bio-fuels requires selective cleavage of CO bond in the reactants to form hydrocarbons by catalytic hydrodeoxygenation (HDO). Generally, Ru metal catalysts exhibit the outstanding hydrogenolysis activity, leading to excessive cleavage of CC and CO bonds, and give large amounts of lower alkanes. In this work, Ru promoted MoO3−x/C catalysts were simply prepared using step impregnation, and successfully applied in the C5–C6 alkane production by the selective CO dissociation of sorbitol in aqueous solution. To screen the optimal reaction conditions, different parameters such as reaction temperature, sorbitol concentration, various transition metals and loading amount of Ru and Mo had been investigated carefully. The experimental results indicated that the Ru-MoO3−x/C catalyst showed the excellent activity with 87.3% yield of C5–C6 alkane and 79.7% yield of C6 alkane on a continuous flow reactor. In addition, the Ru-MoO3−x/C catalyst exhibited superior stability with no observed decrease of activity in 200 h time on stream. Preliminary mechanistic studies supported that the reactions occurred via a selective cleavage of the CO bonds and the synergetic effect of the hydrogenating Ru sites and the active MoO3−x species was the key to such unusual reactivity.